As a drive device installed in a vehicle, already known is a device where a rotating electric machine is provided in a power transmission route between an internal-combustion engine and a drive wheel, and the rotating electric machine controls torque and rotational speed to be transmitted to the drive wheel in the rotating electric machine. For example, known is a drive device which comprises a rotating electric machine and controls torque and rotational speed in the rotating electric machine, the rotating electric machine being provided with a stator; a first rotor being arranged at the inner side of the stator and having magnet; and a second rotor being arranged at the inner side of the first rotor and having coils, which are provided coaxially in a relatively rotatable manner (see the patent literature 1). In addition, there are the patent literatures 2 to 4 as prior art literatures relating to the present invention.